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From what I read, the author mentioned about the word "almost" which implies that per one induction stroke, there will normally be enough oxygen to optimally burn the originally intended fuel. Once the fuel is switch into alcohol fuel, the burnable fuel with the inducted air will normally have...

just curious. Back in the 90s, we moved from nikasil coating to hypereutectic blocks because the nikasil coating got severely compromised by high sulfur fuel in various markets. Iron liner is a bullet proof solution for an aluminum block thus I am wondering why nikasil coating is needed in the...

Steve, From my standpoint, I had enough of all the negative points that come with close coupled catalyst. While it is true that by the time NVH come there is not much we can do about it, however things may change if we have a better solution in advance.

Greg, For the integrated manifold, I dont fancy the sound. Have you done any noise comparison comparing integrated manifold with the old school individual runners with underfloor catalyst? I feel that at certain frequencies, integrated manifold give strange noise

Greg Locock, Your comments seem to suggest that you know about engine aftertreatment. What is your solution to the problems that I have posted yesterday?

too much backpressure, too much overfuelling to keep the catalyst temperature down, bigger capacity fuel injector and pump required, too many bricks required, no more exhaust tuning opportunity with the runner joined together, too many lambda sensors required, etc. The list is too long for...

how about combining secondary air and electric heater?

There are supporting technologies like electrically heated catalyst and secondary air, have we tried all these?

Mike, There are so many turbo engines and the catalyst is placed right after the turbine. This is where I am wondering on whether underfloor can still be used for naturally aspirated

HC and CO limits for EURO 5 and 6 are the same thus the aftertreatment solution now for HC and CO will still be valid few months from now. However, that is still not my question, I am more interested on whether there is still potential of using underfloor nowadays?

The integrated manifold does not come free as well. The heat that should be rejected to the exhaust tailpipe will now have to be cooled by the coolant and rejected to a bigger coolant pump and radiator. There are also patent royalties that automakers have to pay. This goes back to my earlier...

Hi Brian, Nowadays, the use of turbocharger will push away the catalytic converter from the exhaust port similar to the old days naturally aspirated engines. In my view, I am questioning on how much works have been done in the past to make underfloor catalyst to still achieve the Federal -7C...

Hey guys, I am wondering on whether anyone here has any ballpark figure in terms of HC+CO emissions or catalyst lightoff difference between close coupled catalyst and underfloor one?

TSLexi, Why not use oxygen. The chinese researchers use onboard oxygen generator for the oxygen supply. You can burn low quality fuels without HC, CO and PM problems.

HI TsLexi, Send my regards to Mr Crower. For the hot steam corrosion, there are several coatings used by the steam turbine engines that you can apply to the piston top surface, combustion chamber and valves. It will also help for you to inject the water upward rather than downward. Attach the...

Tbuelna, I beg to differ. We have a full test data to link high oil carry over from PVC breather to increased knock tendency. Not all engines in the market have oil carry over of less than 1 g per hour

Tbuelna, The condition that you described easily available before and during the spark ignition. Even Heywood's book discussed the hydrocarbon molecular structure and how it can affect knock tendency. Oil can still get into the combustion chamber through the PCV breather and it is bad if the...

Hey guys, I noticed that many european automakers have started to dump not just charge air cooler heat into the low temperature coolant circuit. There are many patents and papers where the low temperature circuit is also used to cool off AC condenser, EGR cooler and electric motor on top of...

back in 2012, SWRI published a paper linking the engine oil temperature with gasoline knock rather than diesel one. I wont worry much about the effect of engine oil property in diesel engine.

blacksmith, the question that I have, how come countless durability tests could not cause the conrod to be broken into two but neutral high revving and rpm overshoot during gear shift can easily broke one.